In a world without the fine electronics that we have today, would space travel be possible?
....I'm not averse to small amounts of magic in my steampunk worlds, but I'd like to keep it to a minimum, if I can. So possible answers are allowed to stretch practical reality a bit, but not too much.
The Mercury spacecraft didn't have a flight computer. All the controls it had were 55 electrical switches, 30 fuses, and 35 mechanical levers. Those types of electronics are usually easily replaced by steampunk equivalents. It already was missing the fine electronics we have today. Not too much of a stretch at all.
I'm not aware of rockets being off limits for the steampunk toolbox, so you should have no trouble using those as well. You will pretty much have to, you won't get there on steam. However, once you've gotten to space steam comes into play again. There are actually proposals for making steam powered space ships using interplanetary ice for fuel.
In this proposal, the ship encases itself in ice to provide protection from radiation (I'm assuming) and as the source of material for ejection matter.
You may be onto something for steampunk in space.
One of the most significant differences between steampunk and contemporary technology is the computing style.
Despite excellent counterexamples such as The Difference Engine, steampunk is, aesthetically and conceptually, much more natively analog than digital.
Most people these days are unfamiliar with analog computing. I wrote a blog post, The Crafted World of Analog Computing, that lays out a lot of the differences between digital and analog work. Here's a partial summary:
Digital computing manipulates finite state logical machines; analog computing manipulates physical properties such as length and angular position.
Digital computing works with discrete integer numbers and must emulate infinitesimal math such as trig or calculus; analog is natively infinitesimal and must emulate integer math by engraving precise marks on a physical component.
Digital computing implements algorithms in software; analog computing implements algorithms in hardware.
Digital computing breaks logic down into the smallest feasible steps; analog computing is holistic. An analog computer is purpose-built to solve a particular kind of problem.
Digital computing tends to puke and die when confronted with feedback loops (we call them "race conditions"); analog computing relies on feedback loops.
The obvious implications are that digital computing is much cheaper, once you have implemented a computational mechanism with adequately fast switching times, and adequately general logic (e.g. Lambda Calculus.) This is why digital computing has, in our primary world, swamped analog computing: the cost of handbuilt machines, purpose-built to solve one kind of problem, is extremely high compared to general machines that execute cheaply modifiable software.
This, however, is an economic consideration. In steampunk, it's more about feasibility and style than about cost/benefit maximization.
In terms of computing power, analog machines can readily accomplish tasks that are simply hard programming problems for those of us who write digital software - especially systems and control problems, which involve feedback loops.) Most of the problems involved in engineering and navigating a spacecraft can be neatly solved by analog computation and analog control systems.
Expensive technologies that require a lot of craftsmanship are one of the essential characteristics of the steampunk aesthetic. :-)
I think the biggest issue would be communication. I can't think of any way to build a radio without electronics. Maybe really good telescopes and large mirrors? Or communication magic.
Piloting could be done manually with assistance from large paper tables and some slide rules or mechanical calculators. The trajectory would be precomputed and the spacecraft would have on paper the necessary data to calculate the deviation from the expected trajectory and the proper corrections to make. It would be less efficient than computer controls, but I doubt the difference would be that big.
Trajectories could probably be calculated with mechanical analog computers. They were too heavy and required too much maintenance to use in a spaceship, but in a ground based installation they probably could get the same capability as digital computers circa 1980s. Not sure, but mechanical computers would certainly have the capability to do all the math necessary. And the reliability and maintenance issues might actually get solved, if mechanicals were not replaced by digital computers.
In Victorian steam-punk the thought of going to space for various reasons have been discussed. The most interesting technology is the Verne Gun, a large gun on the ground using mostly gunpowder but also other technologies to send materials into space.
Even though this makes problems like air resistance and the fact that the object cannot make orbit. Real life attempts such as the HARP project, was initiated, mostly as a way to cheaply transport cargo into space. But mostly unsuccessful (400kg was effectively send out 180km with 33% escape velocity).
The upside of the Verne gun is that it does not have to have a mass pushed away such as normal rockets, but instead propels the mass using either coil/rail technology or gunpowder.
Have you read HG Wells 'The First Men in the Moon'? Cavorite is the go to material for Victorian space travel as it negates gravity. From the Wikipedia entry which explains it all:
Bedford befriends Cavor when he learns he is developing a new material, cavorite, which can negate the force of gravity.
When a sheet of cavorite is prematurely produced, it makes the air above it weightless and shoots off into space.
Cavor hits upon the idea of a spherical spaceship made of "steel, lined with glass", and with sliding "windows or blinds" made of cavorite by which it can be steered, and persuades a reluctant Bedford to undertake a voyage to the moon
It's a most excellent book one which any Steampunk enthusiast should read. There are also a couple of film adaptations my favourite of which is this one as it features a great British cast. There's even kits of the sphere available!
A heat shield for reentry might be easier than you'd think. Early retrievable spy satellites used balsa wood for their heat shield.
I would start the journey upward with a hydrogen balloon, we all know steampunks have a soft spot for airships... This may sound a little absurd but for $75k you can catch a ride to the "edge of space" and spend a couple of hours at 98,000 feet. So, balloons could reasonable get you started.
But that would only be about 1/6 of the way to what most people would consider "space" so we'll shoot for low earth orbit at about 160 kilometers up. To push the rest of the way we're probably going to need rockets. Big Rockets. But rockets seem to be well within the acceptable bounds of steampunk.
Now once we've made it to low earth orbit we have some technical issues to consider. Could steampunk tech reasonably hold up to the vacuum of space? Most likely yes! If the you're basing your tech limits on the 19th century keep in mind that they were developing submarines as early as 1850. It stands to reason that if they could make a vessel that could withstand the pressures of the deep sea they could build a vessel that could maintain air pressure in space.
Now we've gotten into space and we're "reasonably" safe, how long can we stay? Well that depends mostly on life support, primarily filtering out CO2. And here's a solution:
Some have suggested greenhouses, and while that's certainly within the limits of Victorian technology, a greenhouse big enough to do the job would have to be larger than our ship. So, maybe we do add a greenhouse to the design, but more for aesthetics than practicality - always a big steampunk consideration.
NASA used filters impregnated with lithium hydroxide to remove CO2 from the air of the Apollo capsules. When exposed to CO2, lithium hydroxide sucks it out of the air forming lithium carbonate and water. One gram of lithium hydroxide can remove 450 cubic centimeters pf CO2. The process actually made so much water the Apollo crews actually had to dump the excess overboard. A lithium hydroxide filter with simple electric fans to circulate the air would make an effective life support system for our aether ship and reduce the amount of water our expedition would have to carry.
Lithium hydroxide is not a high-tech material. It was first obtained by electrolysis in 1821 by William Thomas Brande. The process was improved in 1855 by Robert Bunsen, the inventor of the Bunsen burner. So the life support system of our modern moon missions employed essentially Victorian technology.
The problem is not going to be electronics, it will be chemistry and metallurgy.
It's easy to build a mechanical computer, and anyone who's played Kerbal Space Program can tell you that you can get into orbit with just human reflexes alone.
The things that will be obstacles to your steampunk astronauts will be life support and making materials capable of handling the aerodynamic stresses involved.
The main thing you need to build a rocket is reaction mass and heat. You heat up the reaction mass and throw it out the back. The hotter it is, the more pressure, and the faster it goes out the back. Water is an OK reaction mass, steam is better, but still woefully low ISP, but supercritical steam can be an excellent reaction mass.
A supercritical fluid is one under such enormous pressure and of such high temperature, that it becomes nearly impossible to tell the liquid and gaseous phases apart. Supercritical steam has the interesting property that it is denser than liquid water, yet is still compressible. It is also under incredible pressure and heat (22 MPa at 600C), which gives it a lot of energy.
The problem then becomes not only how to generate the pressures and heat needed, but to make a material strong enough to confine the supercritical steam. 22 MPa is about 3200 psi, which is a chamber pressure higher than any rocket humans have built to date with the exception of SpaceX's raptor at 4300 psi (designed, not achieved). Needless to say, this kind of pressure would be difficult to do with 1800s technology in a way that keeps your thrust to weight ratio.
Another issue is going to be your energy source. You will likely not be able to generate the heat needed with coal alone, mostly because of the amount of oxygen you would need. Most real world designs for supercritical steam rockets require nuclear, which I would assume is not possible in your world.
This is where your magic would have to come in: first in creating some sort of "unobtanium magic alloy" capable of handling the stresses involved, and second in generating the heat required, perhaps using some magic "dwarven forge," "dragonfire," or "phoenix eggshells," just anything capable of making intense heat.
The next problem is going to be life support. You need a way to generate oxygen, but more importantly, to remove carbon dioxide. This is usually accomplished with very pure lithium hydroxide, which reacts with CO2 and pulls it out of the air. The chemistry required to produce this may be on the edge of what 1800s technology can do. You may need to invoke magic again.
But once you've sorted out these issues, your astronauts don't need any specialized electronics to fly in space. They can use a simple sextant as sailors have done for eons to find their position in space, or basic gyros can act as an inertial measurement unit. Simple mechanically based devices can measure orientation of the space craft, provide altitude measurements, etc... Slide rules can be used for any really difficult calculations.
Generating electrical power aboard the ship, and storing it, would be a challenge. A steam driven turbine could generate power, but a safe heat source would be necessary. After all, a modern nuclear reactor is just a steam engine that uses uranium for heat. A steampunk heater would probably use some form of combustion. Like a fuel which carried it's own oxidizer, like a flare...a whole battery of flares in a closed chamber. Or it could be a liquid or a gas that burns and produces great volumes of gas for a turbine, like an auxiliary power unit on a jet fighter. The fuel to make electricity would be used up quickly, so it would just be used to charge storage batteries. The ship would run on the batteries, using just a few meager watts of power, and it would spend much of its time running without power, like Apollo 13. Such flights would be limited to a couple of days. Larger machines could be built which would have an huge module attached to the spacecraft which would be dedicated to carrying power generating equipment, fuel, and storage batteries. It would be abandoned in space when the crew began their reentry in their small capsule. No sense in making a huge and heavy heat shield for a power module.
The Sun, or another star, is a great source of heat. I propose two solutions for an efficient boiler to generate a steam.
